


Subject 362636: Romanov, Natasha A.

by Christina (marvelous_slytherin)



Category: Marvel, Marvel (Comics), Marvel Cinematic Universe, The Avengers (Marvel Movies), The Avengers (Marvel) - All Media Types
Genre: Alternate Universe, Anal Fingering, Anal Sex, BDSM, Blow Job, Bondage, College AU, Dildos, Double Anal Penetration, Double Vaginal Penetration, Exhibitionism, Fisting, Fucking Machines, Graduate Students, Hair-pulling, Hand Job, Medical Bondage, Medical Kink, Multi, Multipe Orgasms, Oral Sex, Plot What Plot/Porn Without Plot, Recording, Sex Toys, Sex experiment, Smut, Spread eagle, Unrealistic Sex, Vaginal Penetration, Vaginal Sex, Vibrators, anal penetration, cunninglus, dubious non con, forcing eyes open kink, heart rate kink, i feel like someone would die from this, is that a thing??, medical experiment, some voyeurism
Language: English
Status: In-Progress
Published: 2018-12-02
Updated: 2019-06-27
Packaged: 2019-09-05 14:03:30
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 6
Words: 12,795
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16812106
Author URL: https://archiveofourown.org/users/marvelous_slytherin/pseuds/Christina
Summary: “First?” She repeated. She squirmed again. “How many phases are there?”Tony smiled wickedly and it went straight to Natasha’s core. She could feel herself beginning to drip onto the chair.“Eight,” Tony answered, his hungry gaze making Natasha gasp and her heart race in arousal.“Eight,” She whispered. Tony nodded. He rested one hand on the chair near her hands and the other hand near her hips, towering over her while he stared at her.“Yup,” he said, scanning her again. “Eight phases. We’re going to see how many orgasms a human body can take.”





	1. Abstract

**Author's Note:**

> This is my first time writing smut so I’m sorry if this sucks lol

Natasha was strapped to a ob-gyn chair, naked. She squirmed in her bonds, testing the leather cuffs on her wrists and elbows. Her ankles and knees were tied in the stirrups, bending and spreading her legs. The cold air of the exam room brushed between her legs, making her shiver. She shifted her hips, feeling the leather that kept them pressed firmly against the chair bit into her flesh. She tried turning her shoulders, but the straps above and below her chest, as well as the one around her waist, prohibited her from moving at all. She sighed, the sound echoing in the empty exam room. The walls were white and devoid of any decorations or diagrams. There were basic cabinets and drawers that lined the walls on her left and right, but the wall in front of her was bare. The door was behind her, so she couldn’t see who entered until they stood at her side. She licked her chapped lips, anxious to get this dumb experiment thing over with. The undergraduate students who had situated her said the two graduate students leading the study shouldn’t take long to meet her. She had no idea who they were, or what exactly the experiment was. She tried asking the undergrads, but they were tight-lipped about it, just repeating what was on the email she received, asking if she wanted to participate.

“A study on the female body’s response to sexual stimuli.” That was it. It was intriguing, yeah. It wasn’t everyday you saw an ad for an experiment on sexual stimuli. Natasha was excited for the process to begin with, but now that she was bound to a chair and no one was telling her what this was about, it was scaring her. She hoped it wouldn’t take too long so she could go back and study for her exams. She wondered what the experiment would be about. Her mind began to reel with images of sexy doctors bringing her sweet climax after climax with new toys. The door opened. She jumped, suddenly feeling guilty at her filthy thoughts.

“-And I’m telling you,” A voice said, followed by the sound of several carts being wheeled across the floor. “Two doubles is not too much.”

“Yes, it is,” Another voice said. Natasha tried to crane her neck to see who it was, but with the combination of her being strapped down so securely, her back to the door and the two people staying behind her prevented her from seeing anything.

“No,” The first voice argued.”It’s not.” They continued arguing, and Natasha debated on whether she should speak up or not. The sound of the carts rolling had stopped and the door slammed shut, but they stayed by the door. She let them go on for a couple more minutes before she cleared her throat.

“Oh, right,” The first voice said. Someone cleared their throat and the carts wheeled closer to her. Soon, there were two carts overloaded with equipment and two men surrrounding her. One of the men had dark hair with a thin goatee and a smirk. The other had tanner skin, glasses and curly brown hair, looking slightly uncomfortable. The man with the goatee scanned over Natasha shamelessly.

“Well, hello,” He said flirtatiously, smiling at her. “Romanov, right?” Natasha nodded, licking her lips. She scanned the man back. He looked like he had a good mix of muscle and leanness, but it was hard to tell with the baggy lab coat hiding his frame. The other man cleared his throat. Natasha turned to him, scanning him as well. He looked on the leaner side, but again it was hard to tell with the lab coat in the way.

“So, are you, uh, comfortable, Miss Romanov?” The man asked, fixing his glasses when he stuttered.

Natasha nodded. “Yes,” She answered softly. “And you can call me Natasha.”

The man nodded, glancing at the man with the goatee.

“Right, well, Natasha,” The goateed man said. Natasha turned back to him. “Just to go over who we are real quick.” He pointed to himself. “I’m Tony. I’m an engineering major and-“ He pointed to the other guy. “My buddy Bruce over here is a biology major.”

“Nuclear biophysics,” Bruce corrected quickly. He had busied himself with unloading what looked to be camera tripods from his cart. Natasha gulped. She hadn’t thought about there being cameras. The sound of Tony talking brought her out off her thoughts.

“Right, well,” Tony cleared his throat. “We’re gonna run some tests. As I’m sure you saw in the ad we sent out, it involves sexual stimulation. You’re okay with that, right?”

Natasha nodded. “Yes, I am.”

Tony smiled impishly. “Wonderful.”

There was a loud clatter and Natasha whipped her head over to find Bruce scrambling to pick up a tripod he knocked over. Tony held his arms out and shrugged in confusion.

“Buddy,” He said, exasperated.

“It.... it slipped,” Bruce said sheepishly, scratching the back of his neck before straightening the tripod.

Tony sighed. “Well, I’m going to help my buddy get us set up for the first phase and then-“ Tony started before Natasha interrupted.

“First?” She repeated. She squirmed again. “How many phases are there?” Tony smiled wickedly and it went straight to Natasha’s core. She could feel herself beginning to drip onto the chair.

“Eight,” Tony answered, his hungry gaze making Natasha gasp and her heart race in arousal.

“Eight,” She whispered. Tony nodded. He rested one hand on the chair near her hands and the other hand near her hips, towering over her while he stared at her.

“Yup,” he said, scanning her again. “Eight phases. We’re going to see how many orgasms a human body can take.” Natasha moaned, seized by sudden and intense arousal at his words. She imagined them wringing her out, pulling orgasm after orgasm after orgasm out of her, pushing her to her limits and beyond. She muttered a curse and tried to push her legs together to relieve the pressure in her pussy, but the straps stopped her. Bruce had apparently left the room during their conversation at some point and wheeled in several carts with large monitors on them. He was situating them at the foot of the chair, where presumably he and Tony could read whatever it was that was going to be on them while they worked on her.

_Worked_ _on_ _her_. She gulped again.

“So,” Tony said, gently running his fingertips down her arm slowly, leaving goosebumps in their wake. She gasped, captivated by his rich brown eyes. “Eight phases. Would you like me to break them down for you?”

She nodded, unable to speak.

“So, phase one,” Tony said, raisiing the hand that wasn’t on her arm to count off the processes as he went. He held up a finger. “Just external stimuli. Vibrators, clamps, etc. No penetration.”

He held up another finger. “Simple vaginal penetration. Maybe some other stuff if you want.”

Natasha gasped, squirming again. Tony smiled wider. He lifted another finger. “The third is anal. Just your regular, run of the mill anal sex.”

Natasha bit her lip. A fourth finger went up. “This is where it gets fun. Double penetration in the vagina.”

Natasha whimpered a little. She hadn’t tried any type of double penetration before. Tony smiled and held up all five fingers.

“This time, double penetration in the ass.”

She whimpered again and Tony took his hand away from her arm to hold up a finger on his other hand. Bruce stopped what he was doing and groaned.

“Tony,” He reprimanded. “Proper terms.”

Tony scoffed and rolled his eyes at his partner.

“Proper terms, my ass.”

He smirked at Natasha and held up six fingers.

“Number six, single penetration in the pussy and double in the butt.”

Bruce glared at Tony.

The goateed man just smirked again and kept going. Natasha felt herself getting wetter and wetter by the second.

“Seventh time around, double in the pussy, single in the ass.” He held up eight fingers. Natasha wondering if she would get to feel his fingers inside her, pressing all of the right buttons to get her screaming. She bit her lip.

“In the eighth round we’re gonna give you two in the ass and-” Tony glanced at his friend. Bruce shook his head.

“Tony,” Bruce warned.

Tony shrugged. “And,” Tony started but Bruce interrupted.

“We went over this,” Bruce argued. “We decided it was too much of a risk. We can’t.”

“Yes, we can,” Tony spouted. He focused his attention on Natasha and finished his thought. “And if you want, we can go for round eight, which is double in the pussy and double in the ass.” Natasha gasped. Was that even possible? It sounded like it would tear her apart. She whimpered and squirmed, unsure if her racing heart was from arousal or fear.

“Only if you want to,” Tony said. Natasha glanced at him. The man looked at her hungrily again, probably imagining her taking two dicks in each of her holes, and rested his hands on the edge of the chair, fingers close to Natasha’s side but not touching her. She glanced at Bruce. The man looked unsure. Why he agreed to participate in this experiment seemed beyond her. He seemed so uncomfortable. The man ran his hands through his hair. He went silent for a bit while he thought. Natasha noticed he had set up the monitors and was working on the cameras. There looked to be four of them.

“If you want to do it, we can,” Bruce consented, sighing. “It’s a lot and we don’t know how the body is going to respond.” Natasha nodded, thinking it over again.

“Has anyone else done it?” She asked. The two men shook their heads.

“No,” Bruce said. “You would be the first.”

“And we would go slow and make sure you’re doing all right,” Tony said quickly. “We’re not just going to shove things up their and start fuc-“

“Tony,” Bruce snapped.

Tony sighed.

“I’ll do it,” Natasha said. “Worst case, I just sue you guys.” She smiled a little to show she was joking. Well, partially. Tony chuckled and Bruce gulped.

“All right,” Tony said cheerfully. He clapped both of his hands and rubbed them together. “Let’s get this show on the road then, shall we?”


	2. Phase One: External Stimulation

**Notes for the Chapter:**

> I hope you guys enjoy this chapter! Like I said earlier, I haven’t written smut before so I’m sorry if this is complete garage.

The cameras were set up first. There was one directly above Natasha, angled straight down over her naked form. There was one on each side, getting a good side angle and the last camera was set up by her feet, zoomed in at the space where her legs joined, the soft lips glistening with arousal. Each camera had it’s view projected onto the large monitors on the wall in front of her. There were nine of them total, stacked three by three. Since four of them served as large viewfinders for the cameras, two were being used to show her blood pressure and heart rate, along with some other stats. Two more were used to monitor her brain activity, which was easily the most complicated-looking and most intriguing looking out of all of them. There were glowing charts and diagrams of presumably what her brain looked like, different parts flashing and blinking as they worked. The last one was used to show the phases of the experiment, which tools would be used, and a slot for the time duration of the process. Bruce was typing furiously on his laptop, writing down whatever he deemed important from the screens. Tony was off to the side, near the cabinets. He was pulling out and examine various dildos, vibrators, clamps and other sex toys. Natasha licked and bit her lips when she saw the size of some of the dildos and heard the angry buzz of one of the vibrators. 

While Tony and Bruce were completing their last minute preperations, a young Asian woman who introduced herself as Dr. Cho walked into the room. She had a quick conversation with Natasha about her health history, sexual activity, etc. She hooked Natasha up to an IV, to keep her body hydrated as the experiment went. She gently pressed various EKG pads on Natasha’s chest, neck, and lower abdomin and slid a scary-looking mesh cap covered with wires and plastic tubes. She must have saw the intimidated look on Natasha’s face because she stopped and quickly explained what it was for. 

“This is just a tool to help us monitor your brain activity during the procedure,” She said gently, showing her various tubes and wires, even putting it on her own head to show her it was harmless. When Natasha was satisfied, the cap was slid over her short, curly red hair, one last check of the EKG pads, IV bag and the tools that were going to be used before Tony wheeled over a small cart with some toys. Dr. Cho left the room while Tony and Bruce hooked the tools up to a small computer below the montitors and tested a few, making sure that the necessary stats were set up to project onto the screen. 

“All right,” Tony said, holding a thin vibrator with a smooth metal ball the size of a grape on the end in one hand, flicking the wire with the other to make sure it wasn’t kinked. “You ready?” Natasha nodded, licking her lips. She was so ready. She had been dripping wet ever since Tony explained the procedures to her. “All righty then.” Tony smiled and nodded to Bruce, who was still typing. “You ready, buddy?”

“Uh, yeaaahhhh,” Bruce said slowly as he typed a little faster. He hit ‘enter’ quickly before standning up and pulling latex gloves out of his pocket. He handed a pair to Tony. The man sighed. 

“You ruin all the fun,” Tony grumbled as he set the vibrator down and pulled the gloves on. Natasha felt another gush of wetness at the snap of the material against Tony’s hands. After a few of the longest seconds of her life, Tony picked up the vibrator and walked toward her, laying a hand on her shoulder and squeezing gently. His touch was both soothing and invigorating. 

“Hope you’re ready for the orgasm of a life time,” Tony smirked. 

Natasha smiled. “I hope you don’t disappoint,” She said coyly. 

Tony chuckled. “I haven’t gotten any complaints.”

Bruce started rattling off numbers and phrases so complicated Natasha couldn’t get any idea what he was saying. It might as well be a foreign language. After a bit, the man stopped and nodded to Tony. Tony flicked on the vibrator, the buzz sounding more violent than it had across the room. Natasha felt her pussy throb. Bruce rattled off some more numbers. She heard something about RPM, which was probably some stats about the toy, but she didn’t care. She just wanted it on her clit. And now. 

Tony seemed to sense her agitation and slid his hand down to her breast, gently rolling her nipple between his fingers. The sensation of the slightly tacky rubber against the sensitive nub made her moan. 

“Subject seems to be aroused by areola stimulation,” Bruce said. He stepped towards Natasha, regarding her as if she was just a lab result, cold and indifferent. Natasha closed her eyes, sinking to the feeling of Tony fiddling with her nipple and the growing lust inside her. 

Suddenly, Tony pressed the vibrator against her clit. She jolted and yelped, unprepared for the powerful shaking tool. Her eyes flew open and she panted, her brain trying to wrap around what happened. It was finally happening. Phase One. Of eight. It was here. No more waiting. She moaned, tugging on her bonds. The leather gently bit into her wrists, making her moan again. She tried to push her hips closer to the vibrator, eager to get more pressure on the nub but Tony gently pulled it away, leaving the toy barely kissing her clit. She groaned in frustration and glared at the man. Tony smirked and laughed, clearly enjoying himself. 

“Subject responds very positively to clitoral stimulation,” Bruce added. Natasha felt a strong jolt of pleasure at Bruce’s words, for some reason the use of ‘subject’ making the vibrations seem more tense. She felt the familiar coil build inside her. She moaned again, louder this time. 

“Subject appears to be near orgasm,” Tony stated, pressing the vibrator heavily against her clit. Natasha screamed, the sensation overwhelming. She felt her legs begin to tremble. She couldn’t open her eyes and her mouth was slack in a silent scream as the pleasure began to overtake her. 

“Subject is also very loud,” Tony added quietly. “Might have to gag her if she gets too loud.” As if Tony was looking for an excuse to follow through with his threat, he removed the hand that was on her breast and placed in on her pubis firmly. Leaving his hand intact with the soft skin, he pushed upward, pulling the back the hood that covered Natasha’s clit. She felt her throat tear a little as she screamed, convulsing violently in her bonds as she orgasmed. 

After either an eternity or a second, the stimulation was gone and Natasha panted, trying to regain her senses after such a power orgasm. She cracked open her eyes. Tony hadn’t moved, hand still pressed against her pubis but the vibrator held away from her clit, still buzzing. Bruce was typing away on his laptop. Natasha glanced at the monitors. She looked like she had just received one of the best orgasms of her life, which she had. She was practically glowing with sweat, chest heaving with harsh breaths, making her ample breasts bounce slightly. A sizeable puddle of her juices had spilled off of the chair, casting a sheen on the floor. 

“We’re gonna have to gag her, Bruce,” Tony said. Natasha glanced at him. “She’s too loud. I can barely hear what you’re saying over her screams.” Tony looked at Natasha with dark lust. Natasha gasped, feeling more arousal build up inside her. 

“I agree,” Bruce said, not looking up from his laptop. Tony set down the vibrator on the small cart with the toys and picked up a red ball gag. He turned to Natasha and shoved it into her mouth. She gagged, surprised at the sudden intrusion. Tony pulled her head up and fastened the gag snuggly but not too tightly around her head. He gently laid her head back down, patting the top of her head. 

“You did good,” He said. “Easily one of the sexiest things I’ve seen.”

“Tony,” Bruce warned, glancing at the monitors now. 

“Sorry,” Tony said sarcastically. “Forgot about the experimenter-experimentee professionalism laws.”

Bruce finally turned away from the screens and walked toward Natasha. When he approached her, she felt the vibrator back on her clit. She yelped and jerked, glancing at Tony. He was smirking, gently rubbing the vibrator in circles over the highly sensitive ball of nerves. She groaned, trying to get away from the sensation. It was getting a little too much for her. And here she thought that she could make it eight rounds. She couldn’t even get through the first one. Bruce seemed to gain more confidence and leaned over Natasha, propping his elbows on the chair. She closed her eyes, his close proximity somehow making the whole thing even more enjoyable. He grabbed a handful of her hair and yanked her head towards him. She whimpered and moaned as her eyes snapped open. 

“You look at me,” Bruce said, his voice calm. He stared deep into her eyes. She fought to keep them open. Tony pressed harder with the vibrator. She groaned and jerked again. “Keep your eyes open. I want to see what they look like when you hit your climax.”

She moaned louder as Tony pressed even harder with the vibrator and violently rubbed it back and forth. The coil inside her stomach was tightening. It was there, almost-

“Now, Tony,” Bruce said, not taking his eyes off of Natasha. Suddenly, the vibrator was gone and something else pressed against her clit. She screamed, frustrated as the coil loosened ever so slightly inside her. The thing against her didn’t move, just stayed there, applying gentle pressure on the bud. She squirmed and groaned, trying to keep her eyes fixed on Bruce. 

“Orgasm delay and denial,” He said slowly, tightening his grip on her hair. “Makes the orgasm stronger. The nerves get more and more sensitive, and the brain anticipates a bigger and bigger release, thus adding placebo.” Natasha groaned and tried to press her hips against Tony’s finger. Suddenly, it was gone. She cried, thrashing in anger. 

“Don’t worry,” Bruce said gently. He planted a quick kiss on her forehead. She sighed at the sudden chaste kiss and stared at him, hoping it was enough for him to let her finish. He started rubbing his fingers against her scalp, soothing her. She moaned and closed her eyes at the comforting touch. They stayed like that for a few moments, Bruce massaging her scalp while she came down from her high. Suddenly, as soon as she forgot that she had been denied an orgasm, Bruce jerked her head up and forced her to look down at her hips. 

“Now, Tony,” Bruce commanded. Suddenly, Tony pressed the vibrator back on her clit, the vibrations stronger than before. She screamed and thrashed, feeling her climax building. Her legs trembled. Her groin was on fire. She felt her eyelids grow heavy. Bruce took his other hand and pushed up on Natasha’s lids, forcing them open. She gasped and gurgled against the gag, staring at her clit being vibrated to pieces. She saw the red flush in her skin as she crept closer and closer to orgasm. 

“Tony, we need more,” Bruce said. Natasha yelped and tried to shake her head no. This was enough. She didn’t need anything else. Bruce yanked harshly on her hair and she yelped again. He leaned close, his breath hot on her neck. “Quiet, slut.” She choked at the sudden derogatory word and moaned. Tony suddenly was holding another thin vibrator in his hand and he flicked it on before pressing it against her clit, just below the first one. 

Natasha screamed louder than she ever had before. Everything when white hot. She thrashed and convulsed so violently against her bonds she thought she might break them. She felt Bruce let go of her head, letting it hit the chair as she trembled through the powerful orgasm. She felt her eyes roll into the back of her head. She felt something burst inside her. Slowly, her vision returned to normal, she was heaving and managed to open her eyes. But, Tony hadn’t removed the vibrators. In fact, he made sure she made eye contact with him before he grinned wickedly and flicked them both to the max. Instantly, Natasha was shrieking again, convulsing and thrashing in the chair. Everything went black. 


	3. Phase Two: Vaginal Penetration

**Notes for the Chapter:**

> Sorry if this is garbage lol

Natasha heard her name when she first came to. She was confused, forgot what had happened. But when she felt the strong afterglow from her orgasms, she remembered. Bruce had taken the ball gag out of her mouth, letting her jaw relax. The brain monitoring system they had on her head had fallen off sometime during the last orgasm, so Tony and Bruce decided they would strap her head down to the chair, preventing her neck from from moving. For extra measure, they also placed a strap over her neck, gently securing it to the chair. It was just tight enough so that when Natasha would try to look up, the leather bit into her neck. She could barely see out of the edge of her vision, leaving her to stare at the blank white ceiling, examining the occasional chip of plaster or paint. Well, she would be staring at the ceiling if she could keep her eyes open. She was so tired. Tony had given her a brief rundown of the first phase; just simple vibrator stimulation. He said that the second orgasm made her squirt, as did the third one. The third one also made her pass out. She was out for about thirty seconds, but still, she passed out from an orgasm. And that was only phase one. There were seven other phases to go. Seven. Natasha shifted in her bonds, her sweaty skin sticking to the material of the chair. She felt a hand on her shoulder. It was Tony. 

“All right, Miss Romanov,” He announced, squeezing her shoulder. The action brought some relief in the aching joint and she let out a soft moan. “We’re gonna head to phase two. My buddy Bruce over here wanted me to let you know that there’s no safe words here. We keep going until you absolutely can’t take anymore.”

“How do you know...” Natasha started to speak but was interupted by a coughing fit. Her throat tore at the actions, raw from her screaming. Damn. This was really going to do her in. “How do you know if I can’t take anymore if you won’t give me a safe word?”

Tony grinned that wicked grin. Natasha whimpered, shrinking in her chair as arousal shot through her, making her groin light up. 

“Oh, believe me,” Tony whispered. He leaned over her, his lips barely brushing her ear. “We’ll know.” Natasha licked her lips.

“Sounds like a good deal,” Natasha whispered, hoping her breath fanned over Tony’s ear like his had done to hers. It seemed to have some effect on him because he leaned closer and took her ear lobe between his teeth and bit down, just enough to make Natasha moan, closing her eyes in pleasure. She felt one of Tony’s hands slide up her arm and wrap his hand around hers, his thumb stroking the back of her hand. Her ear lobe slipped out of his teeth, snapping back into place.

“Ready, Miss Romanov?” Tony whispered. 

Natasha let out a breathy ‘yes’. Tony glanced up and nodded to someone on Natasha’s other side. Her eyes darted to the side, spotting Bruce. He was wheeling a chair over to the end of the chair and settling between Natasha’s legs. He wore latex gloves, adjusting them before beginning to mess with the stirrups. His brow was crinkled with intense concentration. 

“I’m going to move your legs back,” He said, glancing up at her. As soon as their eyes met, his cheeks blushed a bright red and he averted his gaze. 

“Just so I can uh... Get better angles.” Natasha rolled her hips, hardly making any movement against the straps holding her down. Bruce pushed the stirrups back, pushing her legs further apart and closer to her chest. Bruce was satisfied when Natasha’s knees were level with her breasts. He straightened and snapped on another pair of latex gloves over the pair he already wore. He pulled a small table that held containers of dildos. She moaned at the sight, seeing the size of some of them. Bruce glanced up, seemingly startled at her response. Tony just chuckled and ran his tongue over the bit marks on her ear lobe. His other hand trailed down to her breast, gently pinching and rolling her nipple. Natasha sighed, trying to push her chest instinctively toward the sensation. She heard a click and a squelching sound. She could barely see Bruce put down the bottle of lube before he plunged a latex-covered digit into her. She gasped. The finger thrust slowly, in and out. He kept it clear of her g-spot, surely not wanting to stimulate her too much too early. Still, just the one finger after three orgasms was enough to get her moaning. 

“You like that?” Tony hissed in her ear, squeezing her hand and her breast. She moaned.

“Yes,” She admitted, squeezing Tony’s hand back. “Very much. Please, don’t stop.” She saw Bruce nod at the edge of her vision before she felt another finger against her entrance, slipping inside. She moaned at the stretch, closing her eyes. 

She didn’t know how long they stayed like that, Bruce gently thrusting his fingers in and out of her, Tony squeezing her breast and hand while whispering sweet and filthy nothings into her ear. But it was enough to bring her to orgasm, trembling in her bonds. The boys didn’t give her any time to recover before Bruce hooked his fingers and rapidly fucked his fingers into her pussy. Natasha groaned, feeling her eyes roll back into her head as the tips of his fingers scraped against her g-spot. 

“Ohhhhhh,” She moaned, trying desperately to push her hips closer to Bruce. “Oh, please don’t stop. Please.”

“I’m not planning on it, Miss Romanov,” Bruce answered dryly before he added a third finger. 

“FFFFFFFFFFFuck,” Natasha groaned, feeling the knot inside her stomach tighten. “I’m so close. Gah, I’m so close. Please please please don’t stop.”

“Already taking three fingers,” Tony chuckled in her ear, biting her ear lobe again. Natasha moaned. “What else do you need, his whole hand? His dick, maybe?”

“Tony,” Bruce warned. “I’m letting you do the dirty talk. I’m not engaging in sexual intercourse with the subject.”

“Says the guy fucking her into oblivion,” Tony snapped, lifting his head from Natasha’s ear. 

“With my fingers!” Bruce defended. “Not my penis!”

“Please, no one calls it that anymore,” Tony quipped. Bruce was going to say something else but Natasha moaned louder. 

“Oh please please please I’m close,” She gasped, barely able to speak over the pleasure. She was there, almost there. Just needed more. “Please. More. More more more more.”

Tony stopped his bickering with Bruce and let go of her. The hand that had been caressing her nipple pressed against her clit, rubbing it with flat fingers while the hand that had been holding hers twisted her nipple.

“YES!” Natasha shouted before the dam broke. She felt her head and neck fight against the bonds as she convulsed, the leather biting into her wrists and hips. Her orgasm rocked through her knocking her breath away. Again, after this orgasm, the boys didn’t give her any break. Instead, Bruce grabbed a large dildo and slammed it into her pussy, angling it to the tip jammed into her g-spot with each thrust. Natasha felt her eyes well. No, she wasn’t going to cry over an orgasm. No matter how intense. She wasn’t going to cry. She tried to take deep breaths, but each thrust knocked all of the wind out of her lungs. 

“FU-Bruce!” Natasha screamed, squirming in her bonds. It was getting to be too much. “Please... Stop!”

“Rather not,” Tony said. At some point, he had let go of her and seized his beloved thin vibrator. Tony waved it in front of her face, making her scream again.

“No!” She protested. She tried to get out of the bonds. She yanked on the restraints holding her wrists. “No! Don’t! Stop!”

“Don’t stop?” Tony asked. He didn’t wait for a reply before he flicked the vibrator on medium speed. “You got it.” He hunched over Natasha, pulling back the hood on her clit and scrubbing the vibrator against the exposed nub. 

Natasha felt another orgasm break and felt that now-slightly-familiar burst of her squirting. Her vision went all white. Her body was on fire. Her brain was fried. Her body hurt from all the thrashing and convulsing. Suddenly, it all stopped. Natasha choked in surprise, eyes flying open. Bruce had slid back in his chair, the front of his shirt covered in Natasha’s juices and Tony had his hand resting possessively on her stomach. Her chest heaved. She felt the bonds bit into the sore spots of her skin that had been in constant contact with them. She glanced at the monitors. She gasped at the results. Her heart rate was at 190 bpm. Her blood pressure was so high she thought she might be dead. The diagram of her brain was like a rainbow, some parts flashing brighter than others. She saw a small alert saying that her IV bag was low. Then there was Natasha herself. Her skin looked like it had been left in the sun for a week without sunscreen, all red and flushed. Her breasts were bouncing with each breath. Her juices were spilling from the chair onto the floor, making a larger puddle and subtle splashing noises. Natasha closed her eyes. 

“I need a break,” She murmured. “Then I can go to phase three.”

“What made you think that we were done with phase two?” Tony asked. 

Natasha’s heart sped up even more and her eyes flew open. 

“No, please,“ She begged. “Please don’t-“

“Let’s do some fisting, Bruce,” Tony said. Natasha fought against the bonds.

“No! No no no no no no no no no!” She pleaded. “Please please please please no!”

“Gag her, Tony,” Bruce snapped. “Do something or I’m going to loose it.”

Tony quickly grabbed the ball gag and shoved it into Natasha’s mouth. He clapped his hand over it, keeping it there. Natasha screamed, trying to plead with her eyes. Tony was just smirking, looking at her with hungry lust. She switched to Bruce, hoping he would see that she was at her limit. They made eye contact. Bruce stopped squirting lube onto his hand. The man gulped.

“Tony...” Bruce said quietly. “Can you... Make her not... look?” 

“Yeah, sure thing, buddy,” Tony said. He covered Natasha’s eyes with his free hand. She screamed again, trying to beg. She felt something large press against her opening. She whimpered, feeling tears leak from her eyes. The thing pushed past the ring of muscle, making Natasha yelp. She choked on the gag as she tried to take deep breaths against the nearly painful stretch. Again, she got no adjustment time. Bruce just started going to town, curling his fingers and punching her g-spot. Natasha screamed, feeling her voice crack. Something buzzed against her clit. She shrieked, thrashing as another orgasm tore through her. It ended abruptly, when everything went black. 


	4. Phase Three: Anal Penetration

**Notes for the Chapter:**

> Hey! This work is doing way better than I thought it was going to lol Glad you guys are enjoying it! Sorry this one is kind of lame. I wanted to write something for this, but for some reason I just couldn't make it as good as I wanted it to.

Natasha groaned, her throat crackling painfully. The afterglow of the previous orgasm was so powerful it almost hurt. Her shoulders were starting to ache from being stretched above her head and from her thrashing about. She was enjoying a break at the moment. Tony and Bruce were discussing the results of the tests so far, everything from her brain activity, to heart rate charts and blood pressure. They even replayed some of the footage. And seeing herself in the middle of intense orgasms, eyes rolling into the back of her head, shaking and trembling before she convulsed like a madwoman and squirted like a fountain. Natasha lost track of how many orgasms she'd had. She guessed around five, but she wasn't sure. Was it more? Or was it less? She really didn't know. The sight of Tony turning around and walking towards her broke her train of thought. 

"Apparently your drive is going down," Tony said. He stepped behind her, fiddling with the IV bag. Natasha tried to look to see what he was doing, but her head was still strapped down to the chair. "Let's see if we can fix that real quick..." Tony's voice trailed off as he concentrated on something. Bruce appeared suddenly at Natasha's other side and handed Tony another clear bag full of clear liquid. She heard some rustling about, presumably Tony hooking the bag up. A few moments of him working passed before he spoke again. 

"Okay," He said, clapping his hands and rubbing them. "Got you a fresh IV bag. Should get your energy up. We didn't spike it, it's just your regular saline hydration solution. You're quite the squirter, so we want to make sure you keep that up." Tony smiled at Natasha, looking her over. His brow furrowed a bit and he glanced at Bruce. "Hey, buddy."

"Yeah?" Bruce responded, distracted by something on the monitors.

"Think we could let up on some of the restraints?" Tony asked. "I'm thinking we loose the neck strap, the ones on the chest and waist. Keep the leg ones there. Maybe move the arms too? She's gotta be getting tired."

"Sure," Bruce said slowly. He was now scribbling furiously on a clipboard in his hand, gaze darting to the screens occasionally. Tony seemed to take that as a yes, whether Bruce knew what he was agreeing to or not, and undid the straps holding Natasha's neck, chest and waist down. She sighed and squirmed a little at the freedom. The sweaty skin that had been scraping against the leather was irritated and red, but nothing that didn't look like it would last beyond a few days. Tony undid her wrists and help lower them to her sides. She groaned, feeling the pins and needles jab into her shoulder joints. Tony quickly leaned forward and kissed her forehead. 

"You're doing great," Tony said. "We got two phases out of the way."

"And six more to go," Natasha mumbled, feeling her eyes droop close. 

"Yeah, six more," Tony said gently. "Do you remember what this next phase is?" 

Natasha shook her head slightly. 

"Anal," Tony said, his voice taking a different tone, this one slightly darker. "We're going to pound that beautiful ass of yours so hard you won't-"

"Tony," Bruce said sharply. Natasha glanced towards the other man and groaned when she laid eyes on him. He was lubing up a dildo. It was a smaller one, only a couple inches in diameter, but the table next to Bruce had several other dildos, increasing in diameter and length, the biggest one so large it looked like a sandwich from Subway. Natasha gulped when she saw the size of it. "I'm going to start soon. Do you want to do this one, or want me to?"

"I'll do it," Tony said eagerly. He gave Natasha another chaste kiss on her temple before slipping between her spread legs, grabbing the slippery toy from Bruce. The other man stepped to Natasha's side, digging for something in his lab coat pockets. He soon produced two nipple clamps, silver with balls at the ends. She licked her lips, staring at them. Bruce wasted no time, pinching her nipple and tugging harshly. Natasha gasped and arched her back, relieved she could finally curve her spine. Bruce slipped the clamp on, the cold, hard metal making Natasha's nipple sting. She hissed, the pain making her pussy drip. Bruce quickly did the other nipple. After he was done, he flicked the bud. Natasha grunted at the sharp sensation. She thought she saw a hint of a smile on Bruce's face as he did it again, getting the same result. While he was playing with her, Natasha felt something cold and thick against her ass. She gasped, jerking away from the sensation. Tony quickly pulled her hips back, pushing the tip of the narrow dildo past her sphincter. She bit her lip as Tony slid the toy inside, letting her body pull it inside. As soon as she had taken all of it, Tony pulled it all the way out, the tip barely kissing Natasha's hole before plunging back in, slowly. Natasha rolled her hips and moaned, closing her eyes. Tony pressed a firm hand on her pubic bone and ran his thumb in gentle circles over her clit. She moaned again. When she felt a warm, wet muscle flick her clit, Natasha jumped and her eyes flew open, glancing down to see Tony licking away at her clit, fucking her ass all the while. She moaned when he trapped the bud with his lips and sucked, shaking his head to the side. His facial hair scraped deliciously against her inner thighs, making goosebumps race up and down her spine. 

"Oh, fuck yes," Natasha grunted, remembering her hands were free. She reached down and buried her hand in Tony's hair, clutching the thick, dark tresses while he pleased her. Bruce kept playing with her nipples, tugging on the clamps, twisting them, running the tip of his finger over the nipple. Soon, Natasha was having yet another orgasm, yanking hard on Tony's hair and holding Bruce's hand on her breast. As expected, she got no break after she came down from her high. Tony quickly grabbed a large dildo and pushed it up her ass, fucking it at a moderate pace while Bruce grabbed Natasha's face, making her look at him again. She groaned when they made eye contact. His rich eyes were dark with lust and full of curiosity, a very sexy combination. 

"Keep your eyes open, Miss Romanov," Bruce said. "Or I'll have to keep them open." 

Natasha moaned, the threat turning her on even more. Tony's tongue found it's way back to her clit and rolled the tip over the bud, lapping at it. He moaned when Natasha moaned, making her legs start to tremble. Her eyes started to grow heavy. She felt Bruce's thumbs push her lids open, yanking her head back and forcing her to look at him. She moaned even louder. 

"Keep them open," Bruce hissed. Natasha licked her lips, wanting more. Despite her judgement, her hand shot forward and grabbed Bruce's crotch. The man jerked and gasped, tugging Natasha's head closer to him. He rested his forehead against hers as she stroked him through his pants, his gaze never leaving hers. The moan he let out was easily one of the sexiest things Natasha had ever heard. She wanted to make him do it again. She quickly fumbled with the button and zipper, managing to unzip the fly and slip her hand inside his pants, then into his boxers. She gripped his member and he moaned filthily. Tony moaned, the sensation making her clit buzz. Natasha's orgasm broke, making her clench Bruce's member tighter and making him moan. He blew his load, the semen soaking his slacks. Tony moaned again and thrust the dildo into Natasha harder, prolonging her orgasm. When she was just about to come down from it, Tony grabbed the vibrator, flicked it to the max and slammed it against Natasha's clit. Natasha shrieked when Tony used his tongue to vary the pressure of the vibrator. After she hit another orgasm, Tony replaced the dildo with a larger one, not even Natasha any time to adjust. He slammed the toy in and out of her as fast as he could. 

"Fuck!" Natasha screamed, letting go of Bruce and grabbing Tony's hair with both hands. She pulled his mouth closer to her clit. "Yes!" 

Tony chuckled, the vibrations sent Natasha spiraling into another powerful orgasm. This time, she stayed conscious after it, and Tony pulled off vibrator and dildo. She gazed at Tony with heavy eyes, panting and heaving. 

"God," Natasha swore. "That... wow."

"Oh, you're still awake," Tony tsked. "That won't do."

Everything inside Natasha lit on fire when Tony pressed his mouth back onto her clit, spreading her lips wide so he could catch everything she squirted at him. 


	5. Phase Four: Double Vaginal Penetration

**Notes for the Chapter:**

> Hey guys! Sorry it's been so long since I updated this. I'm changing the tags on this since some more fun was added to the story. Enjoy!

Natasha groaned, opening her eyes. The harsh white light of the laboratory pierced her retinas, making her whimper. Something touched her hair.

“You’re all right,” A voice said, soothing her. A hand ran through her short curls, gently undoing the knots that had formed throughout her thrashing.

“What phase?” She asked.

“We’re going to start phase four,” The voice answered. She could tell it was Tony, so he was probably the one stroking her hair too. “We’re doing double in the pussy.”

Instead of arousal, a twinge of discomfort went through Natasha.

“I don’t think I can do it,” She said quietly. Her vagina was sore from all of the pounding it endured in the first three phases, and her clit seemed to be permanently buzzing, thanks to Tony’s vibrator.

The man chuckled. “Oh, I think you will. You signed the contract after all.”

Natasha whimpered again. She finally opened her eyes, meeting Tony’s gaze. His hair was wild and messy, his face was flushed and it looked like his skin was glowing. She heard some typing and turned her head, seeing Dr. Cho on her other side, taping away at a laptop perched on a cart. She saw the head monitoring device that has been on her during the experiments.

“Dr. Cho is just gathering some data,” Tony explained. “We started doing a little catch-up while you were out.”

“How long was I out?” Natasha asked.

“About an hour,” Tony said. He paused and looked contemplative. “Yeah, about an hour.” He removed his head from her hair and shifted down to her legs. “We’re also going to switch things up a bit, position-wise. You’ve been laying like this for a couple hours, and we don’t want you getting numb.” Tony smirked.

“I don’t think that’s possible,” Natasha grumbled, sighing as Tony undid the remaining bonds on her legs. The cool air of the lab brushed against the hot, sweaty skin, making goosebumps race up her legs. Tony slowly adjusted the stirrups so her legs weren’t tucked to her chest anymore and helped her lift her feet out of them. Natasha groaned, feeling a bit of pins and needles stabbing her hips and knees as her legs straightened. She sat up, wincing at the snapping sound of her sweating skin peeling off of the leather seat. Once she sat up, Tony gripped her arm.

“We’re gonna switch you around,” Tony said. “You’re going to stand at the side of the table and bend over. We’ll strap you down that way.”

“Standing?” Natasha asked, as she scooted forward, feeling the painful snap of her legs lifting off the seat. “I doubt I can stay standing during all this.”

“We’ll make sure you’re secure,” Tony said, a slightly mischievous tone in his voice. Natasha reached her feet and let Tony guide her to the side of the table. She rested her hands on the surface while he fixed the stirrups so they were pointed towards the ground, of the way. Then he stood next to her and placed a hand on the middle of her back.

“Okay, lean forward and rest your chest on the table,” Tony instructed, gently pushing on her spine. Natasha did as he said, resting her upper body on the table at a ninety degree angle. The width of the table was short enough so her hips and head hung off either side. It was also at a height were her feet could be planted flat on the ground. She sighed at the weight of her body pressing her sensitive breasts underneath her. Some of the table, were she hadn’t been laying on it, was cooler than other parts. The tops of her breasts rested on the cool part, making shivers run through her and her nipples instantly harden.

“Are you comfortable?” Tony asked. “You’ll be like this for a while, so do you need help adjusting anything?” Natasha shifted her body, pushed her breasts up, and rested against the table again. Her breasts, at a decent C-cup, acted as a little cushion for her body. She made sure she was as comfortable as she could get before nodding.

“Words please, Miss Romanov,” Tony said, a finger brushed gently down her spine.

“Y-Yes,” She said shakily, feeling Tony’s finger reached the beginning of her ass, making her tingle.

“Good,” Tony said. “God, I could take you right now.” The last part was to himself, but Natasha licked her lips, feeling a bit of arousal creep back into her. He grabbed a handful of her butt cheeks in each hand, squeezing them harshly. Natasha jolted and gasped, hands gripping the edge of the table. Tony let go, running his palms over her soft flesh, the sensation so soothing it made Natasha close her eyes and moan. His hands slid up her sides, feeling her hips and waist. She felt him lean forward, his body radiating heat as he planted gentle, shiver-inducing kisses along each of her vertebrae, working his way up her back. When he reached the back of her neck, he was practically laying on top of her. Not that she was complaining, it actually felt kind of nice, for some odd reason, to be smashed between a man and a table. She felt something hot and hard against her crack. She gasped when she realized what it was.

“Bruce will show up any moment,” Tony whispered into her ear. “Let’s make this a very quick quickie, shall we?” Natasha whimpered, suddenly excited to feel a real dick inside her instead of a fake one. Tony straightened, his weight and heat leaving her. She heard the rustle of him undoing his pants and she wiggled her rear, taunting him. Tony chuckled. She sighed a little when she felt something hot and hard rest against her ass hole. She gripped the table edge, bracing herself for the penetration. She heard Tony sigh as he begin to push.

“Tony!” A shout echoed through the lab. Natasha and Tony jumped, his dick slipping away from her entrance. She glanced up, spotting Bruce near the door of the lab. He too had disheveled hair, a flushed face and he was fixing his shirt, which was untucked from his slacks. Natasha smiled when she remembered that he came in his pants in the last phase. “No sex with the subject!”

Tony sighed. “C’mon, buddy,” Tony said. “Look at her! I mean, how can you not?”

“Tony, no,” Bruce said, firmer. Natasha pouted.

“Maybe another time,” She said, pressed her hips back. She found Tony’s crotched and grinned against him once. Tony choked on a moan, making Natasha giggle. Bruce sighed.

“Let’s start phase four,” The man said, straightening his glass and walking behind Natasha. She tried to crane her neck and see where he was going but Tony pressed his hand against her back, forcing her to stay put.

“We gotta get you tied down,” Tony said. “Bruce, buddy, can you hand me the rope?” Natasha bit her lip and held back a moan. A few second passed and she heard Bruce hand Tony the rope, the two of them talking about some sort of machine. She wasn’t even going to try and understand what they were saying. She relaxed, letting her head hang off the table.

“Spread your legs for me,” She heard Bruce said. She shifted her legs wider, making more of her weight press against the table. She felt the soft bite of the rope against her ankle as Bruce wrapped the material around the joint. As he secured her ankle to whatever he was securing it to, probably one of the table’s support things, Tony appeared in front of her. She looked up, smiling at him. Her mouth was level with his hips and she could see clear as day how hard he was. She examined his length, admiring his girth and licked her lips. If Tony noticed what she was doing, he chose not to react.

“Give me your arms, please,” He said, crouching down in front of her. She rested her arms over the side of the table. Tony took her wrist, on the opposite of her body that Bruce was working on. “Is she secure?” Tony asked, his voice loud enough so Bruce could hear him.

“She’s loose enough to move a bit,” Bruce answered.

“Kay,” Tony responded. He wrapped the rope around her wrist a few times before pulling her arm down and at an angle, towards the corner of the table. He tugged a bit, enough for her shift a little on the table. She gasped a little and used her other arm to steady herself.

“We’re just making sure you won’t be able to fall off or anything,” Tony said. Then he smiled wickedly. “Or move, for that matter.” Natasha whimpered as Tony tugged again, making her slide forward on the table. Now she was far enough forward that her toes on the foot Bruce was holding could just barely graze the cold, hard floor.

“Okay,” Tony said to Bruce. Then the two men, in sync, secured her ankle and foot to the table. They moved and did the same thing for her other arm and leg, leaving her spread eagled and bent over the table. She felt the cool air tickle her sweaty back and sensitive pussy. She squirmed, feeling arousal build.

“I’ll get the machine,” Bruce said. “You mind finishing up?”

“Yeah,” Tony said, standing. Natasha heard Bruce walk a short distance away and begin to roll something towards her. Tony grabbed her hair and lifted her head, making her look up. She gasped, enjoying the slight sting. He looked down at her.

“We gotta make sure we can see your pretty little face as you come,” Tony said softly, almost to himself. His brow pinched in thought before he smiled. “Got it.” He let go of her head, hurried out of her line of sight and returned, holding another length of rope. Natasha squirmed, feeling the bonds against her wrists and ankles bit into her sensitive skin. Tony bent over her, lifting her head again. She felt him do something to her hair, a few of the strands being yanked painfully. Tony was courteous enough to apologize when she yelped, then continued to work. Then he walked around the table to her back side and she felt the rope against her hips. It felt like he had two strands, one on either side of her. Then she heard him scurry around the table again. He knelt in front of her and crouched down, reaching under the table. He straightened, holding the rope in his hands. She gasped when she realized what he was doing. He glanced up at her, smirked at her gaze and gently tugged. Her head was yanked up, neck bent at an almost painful angle. She groaned at the sensation, strangely aroused. Even though she couldn’t move her head, she moved her eyes to see Tony tie one of the ropes to her wrist before tying the other one to her other wrist. It was then that Natasha realized that she was directly facing one of the cameras. She could see a little bit of her reflection in the lens and groaned when she saw the little red light, signaling that the camera was recording. She gasped and moaned at the sensation, being completely stretched out and vulnerable, the hints of pain pleasurable. Tony stood and clapped his hands together, wiping the dust off them.

“Ready whenever you are, buddy,” Tony said, looking behind Natasha. As if on cue, she felt something hard press against her vaginal entrance. She whimpered, staring into the camera to see if she could figure out what Bruce was doing. She heard a snap, like a cap coming off some kind of container and something cold and thick drip against her pussy. She gasped and squirmed. The motions made her hair get tugged painfully and she yelped. She heard Tony chuckle.

“Oh, this is gonna be a good one,” Tony said, amused. She heard a scraping noise and saw that Tony was pulling up a chair, sitting at the corner of the table, a few feet from her. She licked her lips when he gently palmed his boner through his trousers.

Before she could make a quippy remark, something large pressed into her vagina. She gasped, feeling inch after inch of thick something push into her. It was moving slowly, agonizingly slow, but it was thick enough so it made her stretch delightfully. She groaned, watching in the camera lens as Bruce stood up and fiddled with something. After what felt like an eternity, whatever it was settled into her pussy, the tip grazing her cervix. She let out a sound that was a cross between a gasp and a moan.

“She took twelve inches,” She heard Bruce say. She groaned, imagining what it must look like from his perspective, her completely spread out and stuffed. “Starting at 60 tpm.” The thing began to move, making Natasha gasp and sigh endlessly as it dragged against her inner walls, the pleasure increasing by the second. It thrusted at a steady pace. Whatever it was never wavered or faltered, fucking her almost robotically. _OH._ It was a fucking machine. She was getting fucked by a fucking machine. She groaned loudly at the realization, clenching her fists when the coil inside her suddenly burst. She convulsed, her head being yanked with her movements. Pleasure swelled throughout her body, leaving her gasping for air.

After her orgasm, she heard Bruce speak.

“Increasing speed to 100 tpm.”

She groaned when the machine increased its pace, fast enough to make her ass jiggle slightly with each thrust. Oversensitive from her however-many orgasms she had received, she felt her climax approaching quickly. She felt drool dribble out of her mouth, which hung open in pure bliss. She opened her eyes, not knowing when she had closed them, and saw in the camera lens that Tony and Bruce were now behind her.

“Think she can take another three inches?” Bruce asked.

“Well, she took your fist fine,” Tony answered.

“My fist isn’t six inches in diameter, Tony.”

“You know what I mean.”

“I actually don’t.”

Tony sighed. “Yes, she can take another three inches. But let’s let her have one more before we shove it into her.”

“All right.”

Natasha groaned at the fact that they were talking about increasing her pleasure and another orgasm broke inside her. She felt a gush of fluid rush out of her pussy. Not exactly squirting, but her body decided that she needed more natural lubricant, it appears. After her high, the speed on the machine was decreased slowly until it was at a stop.

“Adding another phallus to the machine,” Bruce said. Natasha closed her eyes, fatigue settling into her bones. She wanted to hang her head, but with the way she was secured, she could hardly move.She felt a hand on her cheek.

“How we doing, Miss Romanov?” Tony asked. “You fucked to the high heavens, yet?”

“Getting there,” She replied weakly. Tony chuckled. “You mind if I take a break?”

“You’re not taking a break,” Tony answered. She felt something massive press against her. She whimpered, tears building in her eyes.

“Please,” She pleaded. “I can’t take anymore. I want a break.”

“Nope,” Tony said, popping the ‘p’. More tears fell down her face as a large amount of lube was squirted on her entrance.

“All together, the subject will take six inches in diameter, twelve inches in length,” She heard Bruce say. She almost sobbed when she felt the two massive dildos slowly press into her. Suddenly, they pushed past the ring of muscle guarding her vagina and slammed into her. She screamed like a banshee, the stretch more than anything she had ever taken. Drool fell out of her mouth and tears leaked from her eyes as Bruce announced the machine was starting at 60 tpm. The pain maintained the same level of intensity as time went on, the dildos pushing in and out of her at their robotic, slow pace.

“Let me help you out there, Miss Romanov,” Tony said. She didn’t know when he got behind her, but he pressed that stupid vibrator of his against her clit. She shrieked, thrashing against her bonds so violently. Even with the pain, she felt her orgasm approaching. Tony increased the speed on the small device and she fell apart, falling limp after the powerful climax. But, of course, it didn’t stop. None of it stopped. In fact, it increased.

“Increasing speed to 100 tpm,” Bruce said. Tony turned up the vibrator again and Natasha whimpered, her voice going raw. The machine was pounding her so hard she was sliding across the table. It felt like everything within her was on fire. She felt the familiar pressure building again. She felt a hint of pleasure. She tried to focus on that instead of the pain. The pleasure started to grow, because of her focusing on it or her body adjusting to the assault, and Natasha orgasmed again.

“140 tpm.”

Bruce’s flat voice contradicted sharply against the violent, brutal fucking the machine was giving her. She screamed as the pleasure officially took over the pain, tears streaming down her cheeks and another orgasm racked her body. Everything went black.

***

When she woke up, she felt her body shaking. She blinked, trying to still her body. It wasn’t working. She straightened. Or, tried to. Something stopped her. She blinked again and glanced around. She was still on the table, bent over and bound. Her head was free now, so she lifted her sore neck to see if she could see Tony and Bruce. They were both sitting in chairs in front of her. She whimpered and licked her dry lips when she saw Tony was reading some type of paper, one of his hands gently stroking Bruce’s dick through his pants. Bruce was squirming in his chair, hand shoved in his mouth to try and hide his moans. Natasha glanced over at Tony and saw him gazing at her. He just smiled and dropped the paper he was holding on the ground. He slid to his knees and broke Natasha’s gaze. He settled in front of Bruce, still stroking the man. He quickly undid Bruce’s pants and pulled his dick out of his trousers. Bruce gasped and let out the most adorable squeak as Tony sank his mouth onto Bruce’s length. Bruce groaned as Tony pumped his hand and his head, cheeks hollowing as he presumable sucked Bruce off. Natasha groaned, feeling the want building between her legs.

“Tony…” Bruce moaned. He bit his fist and growled. A few seconds later, his body stiffened, then he exploded. A surprising amount of semen erupted from his dick, leaving Tony to frantically swallow everything and Bruce in a panting, slumped mess. Tony backed away, letting Bruce’s limp dick fall out of his mouth. He kept his hand on it though, and turned to Natasha. He smirked.

“If you liked that,” He said coyly. “You’re going to _love_ this.” Then he rapidly began to pump his hand. Bruce gasped, jolting. Tony lifted his balls with his other hand and pressed into Bruce. The man groaned, eyes wide open in pure pleasure. He started to tremble as Tony fucking two fingers in and out of the other scientist. He probably started nailing his prostate because Bruce screamed and let out another explosion of come. Tony completely let go of Bruce this time, letting the man slump into his chair, panting as he recuperated from the powerful orgasms. Tony looked at his semen-covered hand, then to Natasha. He stood and walked to her. He lifted her head by her hair, gently, and pushed his fingers into her mouth. She eagerly licked and sucked the salty goodness off of Tony’s fingers, wishing she could taste it directly from the source. Tony pulled his fingers away when they were clean and crouched down, getting eye level with Natasha. She felt a little zing in her chest when she met his soft, rich brown eyes.

“Now that Bruce is down for the count,” He said softly, eyeing her. “We could get to what we tried to do earlier.” Natasha licked her lips.

“I’d like that,” She answered, her voice gravelly and rough. Tony smiled and released her head. She let it hang off the bench as he walked around her. He stopped behind her, hands kneading her butt cheeks again.

“Actually,” Tony said slowly. She heard him shift and felt his hands move so he was holding her lower lips open. “Change of plans.” With that, he pushed his warm, wet, glorious tongue into her pussy. Natasha moaned, eyes rolling into the back of her head. This, she was fine with.


	6. Phase Five: Double Anal Penetration

**Notes for the Chapter:**

> Hey guys! I hope you enjoy this one. I tried a couple new things ;)

Natasha let out a heavy groan when Tony pulled away his tongue from her, the two fingers he had inside of her simply pressing against her g-spot. She felt a few drops of something dribble out of her and she sobbed.

“No more,” She begged. “Please, stop. I really can’t take anymore.” Her whole body was on fire, her blood basically boiling and her clit was throbbing so hard it might as well have a heart of its own. Her inner walls were sore, crying in protest at the earlier intrusions they had endured.

And they were barely halfway done.

“One more,” Tony answered. “Just one more, babe.”

“You said that three ‘one more’s ago,” Natasha spat. Tony retaliated by slamming his fingers in and out of her, jabbing her g-spot violently. She shrieked and came in two seconds, feeling liquid squirt out of her. Tony groaned satisfactorily. She felt his stupid ass tongue against her and jerked as he slowly and delicately licked her clean.

“You taste absolutely delicious,” Tony mumbled against her. She felt more tears leak down her face.

He had given her five orgasms just by fingering and licking her. She was dreading the next phase; the double anal penetration. Taking one dick in the ass was enough. But two? She was going to get torn apart. Especially if they stretched her to six inches like they had in the last phase. Tony was also hinting at adding something else, and Natasha was not looking forward to it. Not one bit.

“Are you ready, Tony?” Bruce asked. Natasha glanced up. She was still bent over the table, spread eagled and on her stomach, so all she could see of Bruce was the outline of his boner through his brown slacks, which he had changed at some point to free ones after the few orgasms of his own.

“Yeah,” Tony said, standing up from Natasha. She whimpered when he pulled his fingers out of her, then shrieked when he smacked her ass. As the sting faded, Bruce walked around the table to Natasha’s back side. She felt two hands spread her two cheeks.

“We’re going to need to do some stretching,” Bruce said. She heard a wet sound and a finger push into her ass. She gasped as the finger searched along her walls, slowly, as if he was really conducting some kind of examination. She felt a gush of wetness at the thought.

“Look at that,” She heard Tony say. “Dripping already.” She didn’t have the will to spit a snarky remark back, so she just licked her chapped lips as Bruce slipped in another finger, the stretch adding more pleasure.

“I was hoping we could do another six inches,” Bruce said. Natasha jolted, her heart racing. Bruce’s fingers slipped out of her.

“NO!” She screamed, thrashing against her bonds. “You are NOT going to shove six fucking inches of fake dick up my fucking ass!”

“Get the gag,” Bruce said flatly.

“No thanks,” Tony said, the smirk evident in his tone. “I enjoy this.”

“Tony.”

“Bruce.”

“Now. Please.”

Complaining under his breath, Tony appeared in front of Natasha. She saw the red ball gag and clenched her jaw. She turned her head and sealed her lips. Tony sighed.

“I need some help, Bruce,” He said. Tony grabbed a handful of her hair and yanked her head up. She grunted but managed to keep her lips sealed.

“Do breath control,” Bruce responded flatly. Tony grinned wickedly. He raised his hands. Right before he clasped his hands over her mouth and pinched her nose, Natasha managed to get in a deep breath, filling her lungs with some air. She met Tony’s gaze, ready to prove that he wasn’t going to beat her.

“You can’t hold your breath forever, you know,” Tony said, acknowledging the smirk in her eyes. Natasha shrugged. Well, as much as she could considering how she was bound. Tony sighed. A few more moments passed. Tony dropped the hand from her mouth and checked his watch. Another few moments. Natasha still stared at Tony.

“It’s been a minute,” Bruce said. “Is it in yet?”

“No,” Tony grumbled. “She’s still holding her breath.” Bruce sighed heavily. Natasha smirked, feeling a little surge of pride at her victory.

But she didn’t expect the vibrator.

The vibrator, probably the one Tony kept using, was pressed to her clit and flicked on. Natasha let out a horrible sound, something between a gasp, a groan and a scream. With her mouth open, Tony jammed the ball gag into her mouth and fastened it behind her head. Natasha choked on a moan and a glob of spit that was shoved down her throat. Her climax was already on the edge.

“Okay, we’re in!” Tony shouted. Natasha felt the vibrator pull away from her clit, at the beginning of an orgasm. She groaned again, panting and heaving against the table as pleasure rippled through her weakly before it fizzled out like a lame firework.

“As I was saying earlier,” Bruce said. “We need to stretch her. She’s not loose from phase three anymore, so this one is going to take a little longer than the others.” Natasha whimpered, feeling sweat and tears drip down her cheeks.

“I want to do this one,” Tony said eagerly.

Bruce sighed. “Fine. I’ll be recording and monitoring.” Natasha heard Bruce walk a few steps away before Tony clapped his hands and rubbed them together.

“Ready to get started, Miss Romanoff?” He asked mischeviously.

“Fuh you,” She spat through the gag. Tony just giggled.

“Oh, I will,” He answered. She felt his hands grab her butt cheeks and spread them apart, revealing her tight hole. She instinctively clenched. Tony moaned a little. “Don’t worry,” He said softly. “I’ll do a good job.” With that, she felt a warm breath against her hole and she gasped as Tony gently traced his tongue around her entrance. Shivers shot down her spine as the tip of the warm, wet muscle just barely grazed her ass hole, outlining every little ridge and crease. He pushed the tip of tongue into her and quickly flicked it in and out, like a kitten lapping at milk in a bowl. Natasha convulsed and moaned, tugging at her bonds. God, he was good. Tony pushed his lips against her and moaned, slithering his tongue into her. Natasha choked a loud groan, feeling pleasure rising rapidly. After a few heavenly moments of searching her inner walls with his tongue, Tony sucked, keeping his tongue inside her. Natasha shrieked as she came, the orgasm being prolonged by Tony continuing to suck at her ass hole. When she came down from her high, Tony pulled his mouth away from her. The absence of his warm mouth made her shiver and she felt the cold air brush over her sensitive skin, the feeling heightened by his saliva. She shivered. Tony released her butt cheeks and ran his palms up her sides, feeling her curves. He placed random kisses on her back as she panted, still recovering from the orgasms. Her body was screaming for no more orgasms, but she knew at least a dozen more would be coming. Tony’s lips reached the side of her neck, which was hanging loosely forward since it wasn’t tied up anymore. She sighed, relieved at his gentleness.

“Mind if I fuck you myself?” Tony whispered in her ear. “Want to give you a break from fake cocks. Do you want a real one?” Natasha’s eyes rolled back and she moaned at the dirty talk. And the idea of having a real, hot, throbbing dick inside of her. She nodded frantically. Tony chuckled darkly. He kissed at the spot on her neck directly below her ear. She felt a hand slip away from her side. She tried to push her ass back against him, as best as she could despite her bonds. She heard Tony unzip his pants and her heart leaped in anticipation. Without any quips, Tony eased his dick into her. He kept his head near hers, his warm breath gracing her neck and giving her chills. They sighed in unison.

“God you feel so fucking good,” Tony rasped, breathless. Natasha could only moan. He started thrusting. Her eyes rolled into the back of her head, the warm pleasure seeping into every fiber of her being. She moaned continuously, trying to thrust back against Tony’s hips. She clenched around him, savoring the sexy moan Tony choked on.

“Gah,” Tony panted, thrusting a little faster. “I’m not going to last.”

Natasha clenched tighter, feeling her own end approaching. A few tears leaked from her eyes. The coil inside her belly tightened. A few more thrusts and a particularly hot moan from Tony did her in. She shivered and convulsed, her end triggering Tony’s. He pulled out just before he came erupted on her ass, his hot and sticky cum landing on her butt cheeks. Tony sighed and panted.

“God,” Tony said. “You’re… Fuck.”

Natasha smiled weakly, the post-orgasm buzz turning into that raging fire of pain-pleasure.

“Can she take double now?”

The sound of Bruce’s flat voice made Natasha jump. Tony chuckled.

“Yeah, she’s good.” Tony backed away from her. She whimpered at the loss. She was dreading the cold, insensitivity of the fucking machine after that amazing fuck. In a scary short amount of time, she felt the two large dicks against her ass. She tried to relax, knowing that tensing up will make it way worse. But it was hard to relax knowing you’re about to take six inches by twelve inches of fake dick in your ass. She felt a pair of hands spread her cheeks apart and the two dicks pressed against her. She breathed deeply. As soon as she started to exhale, one quick thrust pushed the dicks past her sphincter. She choked on a scream and stiffened at the sudden, brutal intrusion. Tears pricked her eyes. She blinked, trying to calm down.

“They’re in,” Bruce said. “Starting at 100 tpm.”

Natasha shrieked, scared at the fact that Bruce was going to give her no adjustment time. The two fake cocks slammed into her, punching the breath out of her lungs. They pulled out and pushed back in, making her sweaty skin peel off the table as she began to slide. It felt like her ass was on fire, the stretch not even remotely pleasurable. She groaned, spit dribbling past the gag and her lips. She felt something against her clit. She knew what it was before it even turned on. Tony might as well as marry that fucking vibrator. She fucking hated that thing. Tony pushed the toy a little harder against her clit and moved it in slow circles, stimulating differing parts of her way-too-sensitive clit. Before she saw it coming, she exploded. She heard Tony yell “whoa!” as she squirted.

And of course, none of it stopped.

Tony kept the vibrator on her clit, buzzing it to fucking oblivion while Bruce announced he was increasing the pace to 120 tpm. Barely a minute passed before Natasha crashed through another climax, Tony flicked the vibrator up a notch and Bruce increased the speed of the machine. She sobbed harder, choking on her tears and moans.

“God, you’re so hot like this,” Tony said. “I’m glad we’re getting all this on video because I swear, I’ll be jacking myself off the whole time.”

“The whole time?” Bruce asked. “We’ve been recording for seven hours.”

“Exactly.”

Natasha imagined putting Tony in her spot, tying him down to the table and ripping orgasm after orgasm from his weak body as he sobbed, asking for mercy for it all to stop. The image of a naked, debauched Tony tied to a table as she teasingly jerked him off and Bruce recording the whole thing made her explode, squirting again.

“Ooh, I want to try something,” She heard Tony say. She felt fear rise within her, but she was too tired to move. The vibrator slid off her clit and pushed into her vagina. She came alive, shrieking at the rapid vibrations. She squirted as Tony pushed the tool in further and pressed it against her g-spot. Fire spread through her body. She forgot where she was. She forgot who was giving her pleasure. She forgot her name. She forgot who she was. She forgot she was even real. Pleasure filled every single one of her senses and rendered her brain useless.

Everything went white, then black.

When Natasha came to, she had been moved. She was laying on the exam table, unbound. She groaned at the ache in her ass. She closed her eyes when Tony spoke up.

“Feeling sore already? We have three more phases left.”


End file.
